JPH01141802A - Methanol reforming reactor - Google Patents

Abstract

PURPOSE:To prevent the formation of local heating in a reforming catalyst layer and the pressure fluctuation in an evaporation part by allowing flow of a raw liquid upwards through the annular part between the inner and the outer pipes from the liquid reservoir part of an upright type reactor in which the raw liquid evaporation part and the reforming part constitute a double pipe double layer structure, and heating the raw liquid through the outer peripheral part by the burning gas. CONSTITUTION:Fuel or fuel gas is supplied from the upper inlet 2 of a reactor main body 1, and the burnt waste gas is discharged from side outlets 3. A number of inner pipes 7 connected with a number of openings 5 of a lower pipe plate 6 provided on the lower side of the outlets 3 are disposed vertically up to the vicinity of the upper part, and covered with outer pipes 8 which are closed at the top ends and connected with an upper pipe plate 11 at the lower ends of pipes 8. The raw liquid of methanol or the mixture of methanol and water is supplied to the raw liquid reservoir part 12 formed between the pipe plates 6 and 11 from a supplying part 13. The raw liquid flows upward through the annular part 10 between the pipes 7, 8 while receiving heat from the surroundings and is evaporated and then superheated and sent to the inside of the pipe 7 packed with reforming catalyst 14 to be reformed, and the reformed gas is taken out from the outlet 4 of the lower part of main body 1. The heat transfer medium 16 may be packed in the annular part 10.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is directed to a high-purity hydrogen generator using methanol as a raw material or a methanol reformer as a hydrogen supply source for fuel cells. This invention relates to a methanol reforming reactor in which the vaporizing section (liquid or methanol) and the catalytic reforming section have a double-tube, two-layer structure.

[Conventional technology]

Conventionally, in tubular (multi-tube) type reactors for methanol reforming, the raw material vaporization section and the reforming section were configured separately, and the heating method was a heat medium circulation method. The heating medium heated in the provided heating furnace is sent to the raw material vaporizer and reforming reactor and is used as a heating source.

On the other hand, as a recent technology, one that integrates a raw material vaporizer and a reformer has been reported (for example, JP-A-61-27
5102, JP 62-108704, JP 62-138301).

[Problem that the invention seeks to solve]

The heat medium circulation method described above has the characteristic that the temperature of the reforming section (catalytic reactor) is relatively uniform and heat spots are difficult to form.
2 Generation amount: 10100N/H or less), mobile type (
For example, it has the disadvantage that it is not suitable for use in portable fuel cells.

On the other hand, JP-A-61-275102, JP-A-62-
In the apparatus described in Japanese Patent No. 108704, the vaporizer is of a once-through boiler type, that is, a type in which liquid is supplied from one end of the evaporation tube and complete vapor is taken out from the other end. In this once-through type raw material vaporizer, especially in the case of a normal pressure system, the flow rate in the gas phase section becomes too large compared to the flow rate in the liquid phase section in the evaporation tube, causing pressure fluctuations in the evaporation tube, and furthermore, the reformed gas The disadvantage is that the pressure is not stable.

Furthermore, in the apparatus described in JP-A No. 62-138301, since the vaporizing section is directly heated by a burner in the liquid reservoir, bumping occurs and the amount of evaporation is unstable. No. Publication, JP-A-62-1
Similar to the apparatus described in Publication No. 08704, the disadvantage is that the pressure of the reformed gas is not stable.

Furthermore, regarding the reforming part,
In the devices described in Publication No. 2 and Japanese Patent Application Laid-open No. 62-108704, the reaction tube filled with the reforming catalyst is directly heated by the burner combustion gas, so heat spots (local heating) are likely to occur, and carbon This method has disadvantages such as the risk of deterioration of the catalyst due to precipitation and sintering.

The present invention was developed in view of the above points, and is a methanol reforming reactor that can be made compact, prevent the formation of heat spots in the reforming catalyst layer, and prevent pressure fluctuations in the vaporizing section. It is intended for the purpose of providing.

[Means for solving problems]

The methanol reforming reactor of the first invention of the present application will be described with reference to the drawings. It has a fuel gas inlet 2 or combustion gas inlet in the upper part, a combustion exhaust gas outlet 3 in the side part, and a modified reactor in the lower part. A lower tube plate 6 having a large number of openings 5 is provided in a vertical reactor main body 1 having a combustion exhaust gas outlet 4 so as to be located below the combustion exhaust gas outlet 3. The inner tubes 7 are arranged vertically up to the vicinity of the upper part of the main body, and an outer tube 8 whose upper end is closed is provided so as to cover the inner tube, and the lower ends of the outer tube are closed by an upper tube plate 11. A raw material liquid reservoir 12 is formed between the upper tube sheet and the lower tube sheet, a raw material liquid supply section 13 is connected to the raw material liquid reservoir, and a reforming catalyst 14 is filled in the inner tube. , a porous body 15 for supporting a reforming catalyst is provided at the lower end of the inner tube.

Further, the methanol reforming reactor of the second invention of the present application has a fuel gas inlet 2 or a combustion gas inlet in the upper part, a combustion exhaust gas outlet 3 in the side part, and a combustion gas outlet 3 in the lower part. A large number of openings 5 are provided in the vertical reactor main body 1 having a reformed gas outlet 4 so as to be located below the combustion exhaust gas outlet 3.
A lower tube plate 6 is provided, and a large number of inner tubes 7 are arranged vertically up to the upper part of the main body so as to communicate with the opening, and an outer tube whose upper end is closed so as to cover the inner tubes. 8
The lower ends of the outer tube are closed by an upper tube sheet 11 to form a raw material liquid reservoir 12 between the upper tube sheet and the lower tube sheet, and the raw material liquid is supplied to the raw material liquid reservoir. 13, the inner tube is filled with a reforming catalyst 14, a porous body 15 for supporting the reforming catalyst is provided at the lower end of the inner tube, and at least the liquid phase portion between the inner tube and the outer tube is It is filled with a heat transfer medium 16 such as metal particles or ceramic particles.

[Effect]

Fuel gas and air or combustion gas from a burner are supplied from the top of the vertical reactor body 1, and combustion exhaust gas is discharged from the side of the body 1.

On the other hand, a mixed solution of methanol and water or methanol is supplied from the raw material liquid supply section 13 to the raw material liquid reservoir section 12 . The raw material liquid further rises through the annular part 10 between the inner tube 7 and the outer tube 8, and during this time it receives heat from the surroundings and evaporates, and is further superheated and passes through the catalyst filled with the reforming catalyst 14. sent to the reaction layer.

The raw material gas is reformed in this catalytic reaction layer, and the reformed gas is taken out from the reformed gas outlet 4 at the bottom of the main body 1.

When the annular portion 10 between the inner tube 7 and the outer tube 8 is filled with the heat transfer medium 16, heat can be supplied even more efficiently.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. However, unless there is a specific description, the shapes of the components described in this example, their relative positions, etc. are not intended to limit the scope of the present invention to these, but are merely illustrative examples. Only.

1 is a vertical reactor main body (hereinafter simply referred to as main body 1), which has a fuel gas port 2 at the top, a combustion exhaust gas outlet 3 at the side, and a reformed gas outlet 4 at the bottom. . This main body 1
A lower tube plate 6 having a large number of openings 5 is provided below the combustion exhaust gas outlet 3, and a large number of inner tubes 7 are installed near the upper part of the main body 1 so as to communicate with these openings 5. Arrange vertically until. Further, an outer tube 8 whose upper end is closed is provided so as to cover these inner tubes 7, and an annular portion 10 is formed between the inner tube 7 and the outer tube 8. The lower ends of the outer tube 8 are closed by the upper tube sheet 11 to form a raw material liquid reservoir 12 between the upper tube sheet 11 and the lower tube sheet 6, and the raw material liquid is supplied to this raw material liquid reservoir 12. Connect section 13. Furthermore, the inner tube 7 is filled with a reforming catalyst 14, and a porous body 15 such as a wire mesh is provided at the lower end of the inner tube 7 to support the reforming catalyst 14.

Furthermore, at least the liquid phase portion of the annular portion 10 between the inner tube 7 and the outer tube 8 is filled with a heat transfer medium 16 such as metal particles or ceramic particles, and the space outside the outer tube 8 is filled with hydrogen or methanol combustion. Fill with catalyst 17. 18 is a gas collecting section.

As shown in FIGS. 3 and 4, for example, the raw material liquid supply section 13 has a ring-shaped supply pipe 22 with a large number of small holes 21 drilled inside a flange section 20, and supplies the raw material liquid. Raw material liquid is uniformly supplied to the reservoir 12 from the surrounding area through a ring-shaped supply pipe 22 . 23 is a bolt hole. In FIG. 1, 24 is a banking, 25 is a heat insulating material, and 26 is a gas distributor.

The raw material liquid supplied to the raw material liquid reservoir 12 further evaporates by receiving heat from the surroundings while rising through the annular portion 10 of the inner tube 7 and outer tube 8 filled with a heat transfer medium, and is further superheated. The reforming catalyst 14 is then sent to a catalytic reaction bed filled with a reforming catalyst 14.

Here, regarding the heat transfer medium 16 filled in the annular portion 10, 111 Promote heat transfer from the surroundings.

(2) Forming zeolites to prevent bumping during evaporation of the raw material liquid.

(3) Reduce the volume of the raw material liquid reservoir to improve responsiveness during load fluctuations.

In particular, it is filled in at least the liquid phase of the raw material.

In addition, in the filling part of the reforming catalyst 14, a methanol reforming catalyst,
For example, a pellet-shaped catalyst such as copper-based, nickel-based, platinum-based, or rhodium-based catalyst is filled. In the catalyst bed filled with these reforming catalysts 14, the raw material gas (mixed gas of methanol and steam, or methanol gas) is reformed, and H2,
A mixed gas of Cot, Co, IhO, etc. is obtained, and the amount of heat required for the reforming reaction is supplied by sensible heat of the superheated raw material gas and heat transfer from the raw material gas. The generated gas (reformed gas) reformed in each catalytic reaction tube (inner tube 7) is collected in the gas collecting section 18, and the reformed gas outlet 4
is discharged from the reformer system.

On the other hand, the heat required for the reforming reaction is supplied by the combustion (oxidation) reaction of the fuel gas supplied together with air from the fuel gas inlet 2. , NiO, Co50, MnO
This occurs in the combustion catalyst 17, such as □, and the reaction heat is supplied to the raw material vaporization section (annular section 10) and reforming section (inner tube 7).

Note that although a catalytic combustion method is employed here as a fuel combustion method, a burner combustion method has the same effect. However, the hydrogen purification section (for example, PSA (pressure swingads)
In cases where a low-calorie gas such as off-gas from a fuel cell or H2 electrode of a fuel cell is used as a heat source, a catalytic method is considered to be better in terms of stable combustion. In addition to the above-mentioned off-gas, methanol may also be used as the fuel.

〔Effect of the invention〕

Since the present invention is configured as described above, it has the following effects.

The Fi+ tubular type reactor has the vaporization and reforming parts integrated with a double-tube, two-layer structure, so it can be made more compact.

(2) Although a liquid reservoir system is adopted for the evaporation section, there is no risk of bumping since it is not an open flame, and if the evaporation section is filled with a heat transfer medium, the prevention of bumping will be more reliable. It is possible to generate stable reformed gas without pressure fluctuations. In addition, regarding the reforming section filled with the reforming catalyst, the catalyst filling section is covered with the raw material vaporization section, which prevents the formation of heat spots in the catalyst layer, which is a disadvantage of the direct heating method, and prevents carbon precipitation. suppressed, allowing long-term stabilization of catalyst performance.

(3) Since the outlet of the reforming catalyst bed is in indirect contact with the raw material liquid, the reformed gas is cooled, which is advantageous both in terms of heat recovery and in the low range of CO in the generated gas. . That is, the methanol reforming reaction is CJOH + HzO1Coz + 3H2■COt
+Hz m Co + HzO ■■, expressed as an equilibrium reaction equation of Equation 0, but especially for Equation 0, the gas composition is expressed as an equilibrium relationship at the catalyst layer outlet temperature, and the higher the temperature, the more it shifts to the right, i.e. This results in a CO glitch composition. Therefore, for hydrogen production and recovery or for fuel cells, the lower the catalyst layer outlet temperature, the higher the hydrogen concentration in the reformed gas, which is advantageous.

(4) Since the inlet portion of the reforming catalyst layer is located at the upper part, that is, on the high temperature side, it is advantageous in terms of reaction. The methanol reforming reaction is expressed as an endothermic reaction of the above equation 0, and most of the reaction occurs at the inlet. Therefore, the temperature at the inlet of the reforming catalyst bed can be kept as high as possible, and the heat necessary for the reaction can be efficiently supplied.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the methanol reforming reactor of the present invention, FIG. 2 is a sectional view taken along line A-AvA in FIG. FIG. 4 is a sectional view taken along the line B-B in FIG. 3.

Claims (1)

[Claims] 1. In a vertical reactor body having a fuel gas inlet or combustion gas inlet at the top, a combustion exhaust gas outlet at the side, and a reformed gas outlet at the bottom, A lower tube plate having a number of openings is provided on the side, and a number of inner tubes are vertically arranged up to near the top of the main body so as to communicate with the openings, and the inner tubes are covered. An outer tube whose upper end is closed is provided, and the lower ends of the outer tube are closed by an upper tube sheet to form a raw material liquid reservoir between the upper tube sheet and the lower tube sheet, and the raw material liquid reservoir A reactor for methanol reforming, characterized in that a raw material liquid supply section is connected to the inner tube, a reforming catalyst is filled in the inner tube, and a porous body for supporting the reforming catalyst is provided at the lower end of the inner tube. 2. In a vertical reactor body having a fuel gas inlet or combustion gas inlet at the top, a combustion exhaust gas outlet at the side, and a reformed gas outlet at the bottom, the reactor is located below the combustion exhaust gas outlet. A lower tube plate having a number of openings is provided, and a number of inner tubes are vertically arranged up to near the top of the main body so as to communicate with the openings, and an outer tube plate with the upper end closed so as to cover the inner tubes is provided. A tube is provided, and the lower ends of the outer tube are closed by an upper tube sheet to form a raw material liquid reservoir between the upper tube sheet and the lower tube sheet, and a raw material liquid supply section is provided in the raw material liquid reservoir. In addition to filling the inner tube with a reforming catalyst, a porous body for supporting the reforming catalyst is provided at the lower end of the inner tube, and metal particles and ceramics are added to at least the liquid phase between the inner tube and the outer tube. A methanol reforming reactor characterized by being filled with a heat transfer medium such as particles. 3. The methanol reforming reactor according to claim 1, wherein the outside of the outer tube is filled with a hydrogen or methanol combustion catalyst. 4. The methanol reforming reactor according to claim 2, wherein the outside of the outer tube is filled with a hydrogen or methanol combustion catalyst.